The Chinese ministry of land and resources released the first batch of rare earth mining quotas for 2017.
The total quota is unchanged compared to last year: 52'500 tonnes. The partition of heavy rare earth represents 17% and is unchanged as compared to last year.
Rare Earth Elements (REE)
The rare earths are not particulary rare, being a family of metals with atomic numbers 58 to 71. More than 100 minerals are known to contain one or more of the rare lanthanides. Only two of these minerals, monazite* and bastnasite**, are commercially important. The challenge with rare earths is their natural concentration to form a deposit and then the separation of rare earth elements. A mineral like monazite may contain half a dozen or more different rare earth elements. Today, a standard procedure is available for separating the rare earth elements from each other. In many lanthanides, pure metal is made by treating its fluorine compound with calcium.
The elements Scandium (21), yttrium (39), lanthanum(57) and Thorium(90) usually occur with the rare earths and are commonly classed with them.
The rare-earth metals or lanthanides were divided into three categories by Jöns Jakob Berzelius (1779–1848) :
- The cerium subgroup,which comprised of 57-lanthanum, 58-cerium, 59-praseodymium, 60-neodymium, and 62-samarium (61-Promethium does not occur naturally).
- The terbium subgroup includes 63-europium, 64-gadolinium, and 65-terbium.
The remaining lanthanides are placed in the yttrium subgroup. Strictly speaking, yttrium is not a rare earth. Because the properties of yttrium resemble those of heavy rare earths, its name has been used as a designating adjective.
- The yttrium subgroup includes 66-dysprosium, 67-holmium, 68-erbium, 69-thulium, 70-ytterbium, and 71-lutetium.
The most common lanthanoids in these minerals are, in order, cerium, lanthanum, neodymium, and praseodymium. Monazite mineral also contains thorium and ytrrium.
*Monazite: reddish-brown phosphate mineral containing rare earth (Ce, La, Th, Nd, Y)PO4
**Bastnasite : carbonate fluoride minerals with chemical formula (Ce, La, Y)CO3F